In tunnels and buildings, safety installations are known in which a plurality of distributed electrical consumers, for example lights, are connected to a through line via branch lines. The through line is used for the joint supply of power to these consumers, which are typically situated at a distance from one another along the through line, and which are each connected to the through line via a separate branch line. A flat cable to which the branch line is connected to the flat cable, without stripping of the insulation, by means of a connection device with penetration contacts may be used as a through line. This type of installation is described in the publication EP 2 568 542 A1, for example.
In the event of a short circuit in a branch line, with such an electrical installation there should no functional impairment of consumers that are connected to other branch lines. For example, during a fire, after some time the insulation in the consumer or the branch line burns off and thus loses its insulation capability, resulting in a short circuit between the conductors, which then are no longer insulated from one another.
According to the DIN 410212 standard for functional integrity of electrical line systems, these systems must be designed in such a way that the safety-related installations and devices remain functional for a sufficient period of time in the event of fire. Retention of functionality is ensured according to the standard when the lines meet the test requirements for functional integrity class E90 or E30, i.e., remain functional for 90 or 30 minutes, respectively, when the lines on floor slabs are installed beneath the floor screed with a thickness of at least 30 mm, or are installed in the earth.
An electrochemical element is known from DE 2 248 276 A1, with a metal film that is applied to its outer surface in order to have additional protection from abrasion during handling.